Fabric coated sponge rubber and method of making same



Aug. 11, 1953 s. w. ALDERFER 2,648,619

FABRIC COATED SPONGE lRUBBER AND METHOD OF MAKING SAME Filed May l, 1952 z\ l I2 JNVENToR. 'l2 STERLIN?. ALDERFER BY 30M ATTORNEYS Patented Aug. 11, 1953 FABRIC COATED SPONGE RUBBER AND METHOD OF MAKING SAME Sterling W. Alderfer, Akron, Ohio, assignor of three-tenths to Edward D. Andrews, Akron,

Ohio

Application May 1, 1952, Serial No. 285,513

9 Claims. (Cl. 154-100) This invention relates generally to a sponge rubber product having a fabric backing, and more particularly to a novel sponge rubber product having a non-elastic fabric backing provided with an outer surface of elastic fabric, and the method of making said product. Certain prior fabricbacked sponge rubber products consist of a layer of fabric adhered to a layer of sponge rubber by a layer of adhesive. Such products not only require a separate operation for applying the adhesive, but also are impervious to air because the adhesive closes up the pores of the sponge rubber so that the product cannot breathe or allow ventilation therethrough, and are therefore unsuitable for many purposes as in the manufacture of seat covers, mattress covers, carpet and rug linings, insole linings, etc.

Certain other fabric-backed sponge rubber products have consisted of a layer of sponge rubber which is adhered directly to a layer of fabric by spreading a mass of sponge rubber or latex foam over the top of the fabric, leveling the mass with a scraper or roller, allowing it to gel and then vulcanizing. Such products are pervious to air but have the disadvantage that the foam rubber surface is rough and pock marked due to the bursting at the surface of bubbles of air or gas during the gelling process.

In my copending application Serial No. 156,201,

led April 15, 1950, I have disclosed a novel fabric-backed sponge rubber product which overcomes these disadvantages in that it is pervious to air and can breathe properly because the rubber latex is attached directly t one surface of the fabric by penetration of the latex into the mesh of the fabric, and at the same time the outer surface of the foam rubber is smooth, planished and porous having uniformly distributed microscopic pores. The method of making that novel product is fully disclosed in my copending application Serial No, 156,203, filed April 15, 195).

Many uses for fabric-backed foam rubber products require that the fabric be a knitted textile fabric, rather than woven, to increase the softness and enhance the appearance of the fabric side of the product. For example, for automobile seat coverings foam rubber backed with finely knitted fabric presents a softer texture and a more pleasing appearance than can be obtained with a woven textile fabric. Also, foam rubber backed with knitted textile fabric such as tricot is desired in making certain products such as brassires, because of the soft sheen and delicate appearance of the fabric.

A foam rubber product having such a fabric backing, even though made according to my coits fabric side.

pending applications Serial Nos. 1562011 and 156,- 203 so as to be air-pervious and have a smooth rubber surface, still has the serious disadvantage that the knitted fabric backing is inherently very elastic and allows stretching of the fabric in all directions. This makes it undesirable for several reasons; e. g., the sheet cannot be laid on a table and cut to exact dimensions because of the distortion of the fabric as it is drawn through a clicking machine, and it cannot be satisfactorily used to upholster a chair seat or other furniture or for covering flat surfaces such as mats, because it distorts and stretches out of shape.

The object of the present invention is to provide a novel sponge rubber product and a method of making the same, said product having a knitted textile fabric backing which has all the desirable characteristics of the product of said application Serial No. 156,201, and at the same time is substantially non-elastic in all directions along In other words, the product of the present invention has a vulcanized layer of porous foamed rubber latex directly attached to a soft knitted fabric by penetration of the latex into the fabric, the outer surface of the foamed layer being soft, smooth and planished and having uniformly distributed microscopic pores, and the fabric side of the prod-uct being substantially non-elastic in all directions.

The drawing forming part hereof shows a piece of the nished product comprising the present invention, and also shows schematically a step in lthe method by which the product having all cf the desirable characteristics may be made, but it will be understood that modifications may be made in the product and method which are within the scope of the appended claims.

Fig. 1 is a perspective view of a portion of a sheet of the finished product, parts of the layers thereof being broken away to show the composite construction;

Fig. 2 is an enlarged fragmentary cross section thereof, in which a schematic representation of the microscopic pores or air cells of the sponge rubber is attempted, although the size of the pores necessarily has been exaggerated;

Fig. 3 is a schematic sectional view showing a step in the method of assembling the foamed latex rubber with the fabric layers in making the novel product; and l Fig. 4 is a similar view showing a modification of said method step.

The product of this `invention consists of a layer of sponge rubber with an outer backing layer of knitted textile lfabric and van intermediate layer lof a square mesh Woven fabric which is substantially non-elastic in all directions. The sponge rubber layer I is preferably made by foaming and beating rubber latex with a relatively large volume of air to produce va uniformly aerated mass of latex foam. The volume of air may be from four to seven urnes 'the'volurne of latex. Various types yof beaters may be used for performing this operation, it being yessential that lthe air and latex are so thoroughly mixed that a multiplicity of fine bubbles or pockets are formed, uniformly distributed throughout the latex. A suitable beating apparatus is shown in my copefiding application Serial No. 156,202, led pril` 15, i950. The latex is compounded .with gelling and vulcanizing agents and pigments, usually during the beating operation. I

From the beating apparatus, the freshly foamed latex is ipoured or spread upon a smooth surface "te the depth 'required which .may vary according to the 'requirements of a Variety 'of products, as for 'example from a depth olf one- 'sxteenth 'to on'e-q'uarfter of fan oi' more. The smooth 'suppe'rti'ng 'surface upon which the lfoame'd lateX is spread is lprefer'ably a v-I'noving continuous belt of leather, rubber o1" stainless steel which 'is kept polished land entirely free off dirt or traces Tof old latex. -S-uch `a belt is iii-idlicated at II in Figs. 3 land 4,'supported-onza'suit-- fable 'bed `I"2 traveling iin the direction -of the arrow, and a mass -c`f fresh-1y roamed 'latex as poured from "the beating apparatus Ais indica-ted ,at 113.

As tin 'my prior copending application Serial No. 'i5-65203, the fahne backing fis applied te the vupper 'surface o'f the foained layersuppertelai on the fbe'l't `II, and is preferably 'appiied "to "the iub'ber "foam 'at 'th'e kpoint "where the :foam is reduces 'maintained at' "a required ue'p'th by a doctor Troll Vor doctor b'a'r 14 spaced above ythe b'el-t II, the "'foarned latex messing up in front of Lthe doctor vbar and movin'g through the p'a'ss between the doctor bar and the beit atlthere- `quilt-'eel depth. S 'Shown vin Fi'g. l3, the 'knitted fabric T5 which "is to 'forni the outer lsurface/'of the backing inay lbe brought under Vthe -doctor bar as a continuous strip, and at this point 'a continuousstrip of non-elastic open -mesh woven fabric f6 .is brought under 'the ydoctor bar 'below n and in lcontact with the 'knitted l-'fabric so that the open mesh .fabric Vis in direct Contact with the 'to-psurfaee of the-reduced layer Ill of f earned latex. The #representation :of -the .fabric layers IIE and -I6 the drawings is merely `an attempt to show schematically a contrast between vthe knitted fabric 'layer -I5 `and the woven fabric layerI-B.

As `'the mass 'of lflatex contacts --the lopen A.mesh fabric I6 a slight amount of the water :in-the latex may beabsorbed inthe interstices of the Vfabric strands -fcarrying with 'it .some of .the -foamed latexA `causing -thelatex layer'tc become anchored t'o the open mesh fabric. fAs illustratedin Fig. 2, Lthe bulk-of the Vfea-med Ilatex will passfor strike dthrough the yopen 'meshes into-contactwith-the inner surface of -thel'knitted fabric vlayer `I 5 I'which also -fabsorbs Vrsome yof :the water in the latex to cause the latex tofrmly embed itself in the finterstices -of :the fknitted fabric and become securely anchored =to .the fabric #layer I5. In the case of -most knitted fabrics, thelatex doesfnot-'carry through tothe exposed'sidepf lthe'Miter-fabric layer but penetrates only-fsuiciently -to knit firmly with the fabric. However, with knitted fabrics in Which the latex tends to penetrate or strike through the fabric to its outer surface, the modified method of Fig. 4 is used. In such case, the Woven open mesh fabric is brought alone under and in contact with the vdoctor bar I4 as shown, so that the latex I3 strikes through and substantially covers the upper side of the fabric as it leaves the doctor bar. A second doctor bar `represented by roll I 4a, is positioned a slight distance beyond the bar I4, and the knitted fabric strip I5 is brought under the roll Ida into contact with the upper surface of the latex covered fabric, the height yof roll Illa being adjustable to exert `a slight downward pressure on the strip I5, suiiic-ient to cause only a slight penetration of the latex into the interstices of the knitted fabric, Iand thus prevent any possibility of the latex striking through to the upper surface of the knitted fabric. Thus while the hydrostatic pressure bui-ltup by the latex mass i3 inayfcause excessive penetration, by bringing the knitted fabric in under the second vdoctor roll Ida., the penetration of -the latex into the rknitted fabric VIt is accurately controlled.

The open mesh fabric layer Amay be varied considerably, both as to the kind of material-and las to `the size of the mesh opening. Itis pre-ferably a square mesh Amaterial which may be Woven tobacco cloth or cheese Acloth, or may be woven of rayon or nylon yarndepending on thestrength required. The size Yof the mesh `opening is lpreferably at least four or ve times `the diameter-of the yarn used. For a fabric-'backed 'foamrubber sheet to be used as automobile seat covering material, I have found thata square mesh 4fabric woven from rayon marquisette land vhaving a mesh opening about l millimeter square isla very satisfactory reinforcement for an outer finely knitted soft fabric layer having the 4desired soft feel and pleasing appearance. Somewhat'greater strength can be attained 'by using a anylon yarn. vFor brassire material having an outer fabric layer I5 of knitted tricot, the `intermediate layer I gmay be of `tobacco cloth 4and 'still provid-oeufiicient reinforcement for the `outer layer. The depth of the roamed latex layer LIii alsomayya'ry considerably according `to requirements. "For most uses, `this depth 'may range vfrom iL6'to 1/4, but for vspecific purposes it :may be somewhat Vthinner or substantiallythicker.

According 'to vthe preferred method of `making the novel product, from 'the doctor bar TI`4 or Ilia the belt il moves `the composit'e's'heet of foamed latex with thesuperimposed'fabric layers I 6 `and 'I through Va heated vvoven to set or gel the fo-amed "latex "under the vinfiuence of th'e setting agent, thus preserving theneycellular'structure of the latex. After the foam-is set, the 'coimposite sheet leaves the 'bel-t vand vvis passed through a vulcanizing "chamber-where 'the "fabric may be .held lfrom shrinking by the use of well known tentering Aframes or belts. This method of making theproduct isnot apart oftiiis invention but is disclosed and 'ciaimedin `my cependilrgapplication `Serial No. 5156,203fiiled April 15,

By causing the roamed rubberlatex to set while it is in contact with the sinoothsurface voflthe belt or its equivalent, the outer surface .of the finished sponge rubber layer I@ is given the smooth, velvety surface characteristic of the product of the invention .disclosed .-inmycopending application Serial No. 156,201., and b yrcausing some of the foamed latex to strike through the intermediate reinforcing fabric layer and penetrate into the outer fabric layer, secure adhesion between the sponge rubber and the fabric backing is obtained without impairing the permeability of air through the entire composite sheet. The non-elastic intermediate layer is anchored to the outer knitted fabric layer by the sponge rubber layer and reinforces the outer layer, so that the composite fabric backing is rendered substantially non-elastic in all directions while presenting the desired soft texture and pleasing appearance on its outer surface.

Thus the product of this invention consists of a sponge rubber product backed with knitted textile fabric having a soft texture and attractive appearance but being substantially non-elastic, the composite product being thoroughly air-pervious and being smooth and velvety on the exposed side of the sponge rubber.

The terms sponge rubber and foamed latex used herein are words of description and not words of limitation and are intended to embrace any equivalent material having similar properties. Likewise woven fabric and knitted fabric are intended to cover, respectively, any woven fabric and any knitted textile fabric suitable for the purposes herein set forth.

The invention embodies such modifications and variations as are within the scope of the appended claims.

What is claimed is:

1. A new article of manufacture comprising a vulcanized layer of foamed and gelled rubber latex having a multitude of minute air cells distributed throughout the layer and communicating with each other, an intermediate layer of non-elastic open mesh woven textile fabric attached to one surface of said latex layer by penetration of the latex into the interstices of the fabric, and an outer layer of knitted textile fabric attached to said woven textile fabric and to said latex layer by penetration of the latex through the open mesh of said woven fabric and into the interstices of said knitted textile fabric, the outer surface of said latex layer being planished and characterized by the presence of substantially uniformly distributed microscopic pores.

2. A new article of manufacture comprising a vulcanized layer of foamed and gelled rubber latex having a vulcanized bond with a composite fabric backing, said latex layer having a multitude of minute air cells uniformly distributed throughout and a soft, smooth outer surface characterized by the presence of substantially uniformly distributed microscopic pores, said fabric backing consisting of an intermediate layer of non-elastic open mesh woven fabric attached to the other surface of said latex layer and an outer layer of knitted textile fabric attached to the other surface of said latex layer by penetration of the latex through the open mesh woven fabric and into the knitted fabric.

3. A new article of manufacture comprising a vulcanized layer of foamed and gelled rubber latex having a multitude of minute air cells distributed throughout the layer and communicating with each other, an intermediate layer of non-elastic open mesh woven textile fabric attached to one surface of said latex layer by penetration of the latex into the interstices of the fabric, and an outer layer of knitted textile fabric attached to said woven textile fabric and to said latex layer by penetration of the latex through the open mesh 6 of said woven fabric and into the interstices 0f said knitted textile fabric.

4. A new article of -rnanufacture comprising a vulcanized layer of foamed and gelled rubber latex having a vulcanized bond With a composite fabric backing, said fabric backing consisting of an intermediate layer of non-elastic open mesh woven fabric and an outer layer of knitted textile fabric attached to one surface of said latex layer by penetration of the latex through the open mesh fabric and into the interstices of the outer fabric layer.

5. A new article of manufacture comprising a vulcanized layer of foamed and gelled rubber latex having a vulcanized bond with a composite fabric backing, said fabric backing consisting of an intermediate layer of non-elastic open mesh Woven fabric having square openings each at least substantially four times as large as the diameter of the yarn from which the fabric is woven, and an outer layer of knitted textile fabric attached to one surface of said latex by penetration of the latex through the open mesh fabric and into the interstices of the outer fabric layer.

6. In the method of making a sponge rubber product having a non-elastic composite fabric backing, the steps of depositing a mass of liquid rubber latex on a moving belt in front of a doctor bar spaced above the belt, passing a strip of nonelastic open mesh woven fabric under the doctor bar in contact with the latex causing penetration of the latex through the woven fabric, and applying a strip of knitted textile fabric to the upper surface of said woven fabric in Contact with the latex penetrating through said woven fabric.

'7. In the method of making a sponge rubber product having a non-elastic composite fabric backing, the steps of depositing a mass of liquid rubber latex on a moving belt in front of a doctor bar spaced above the belt, passing a strip of nonelastic open mesh woven fabric under the doctor bar in contact with the latex causing penetration of the latex throught the woven fabric, and. simultaneously passing a strip of knitted textile fabric under the doctor bar in contact with the woven fabric and the liquid latex penetrating therethrough.

8. In the method of making a sponge rubber product having a non-elastic composite fabric backing, the steps of depositing Va mass of liquid rubber latex on a moving belt in front of a doctor bar spaced above the belt, passing a strip of non-elastic open mesh Woven fabric under the doctor bar in contact with the latex causing penetration of the latex through the woven fabric, and then passing a strip of knitted textile fabric under a second doctor bar in contact with the upper surface of the woven fabric and the liquid latex penetrating therethrough.

9. In a method of making a sponge rubber product having a non-elastic composite fabric backing, the steps of depositing a mass of liquid rubber latex between a supporting surface and a layer of non-elastic open mesh woven fabric, bringing said liquid mass to a uniform thickness while held between said surface and said fabric layer, and then applying a layer of knitted textile fabric to the outer surface of said woven fabric in contact with the latex penetrating through the woven fabric.

STERLING W. ALDERFER.

No references cited. 

8. IN THE METHOD OF MAKING SPONGE RUBBER PRODUCT HAVING A NON-ELASTIC COMPOSITE FABRIC BACKING, THE STEPS OF DEPOSITING A MASS OF LIQUID RUBBER LATEX ON A MOVING BELT IN FRONT OF A DOCTOR BAR SPACED ABOVE THE BELT, PASSING A STRIP OF NON ELASTIC OPEN MESH WOVEN FABRIC UNDER THE DOCTOR BAR IN CONTACT WITH THE LATEX CAUSING PENETRATION OF THE LATEX THROUGH THE WOVEN FABRIC AND THEN PASSING A STRIP OF KNITTED TEXTILE FABRIC UNDER A SECOND DOCTOR BAR IN CONTACT WITH THE UPPER SURFACE OF THE WOVEN FABRIC AND THE LIQUID LATEX PENETRATING THERETHROUGH. 